// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2019 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif

#include <randomenv.h>

#include <clientversion.h>
#include <compat/cpuid.h>
#include <support/cleanse.h>
#include <util/time.h> // for GetTime()
#ifdef WIN32
#include <compat.h> // for Windows API
#endif

#include <algorithm>
#include <atomic>
#include <chrono>
#include <climits>
#include <thread>
#include <vector>

#include <cstdint>
#include <cstring>
#ifndef WIN32
#include <sys/types.h> // must go before a number of other headers

#include <fcntl.h>
#include <netinet/in.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/utsname.h>
#include <unistd.h>
#endif
#if HAVE_DECL_GETIFADDRS
#include <ifaddrs.h>
#endif
#if HAVE_SYSCTL
#include <sys/sysctl.h>
#if HAVE_VM_VM_PARAM_H
#include <vm/vm_param.h>
#endif
#if HAVE_SYS_RESOURCES_H
#include <sys/resources.h>
#endif
#if HAVE_SYS_VMMETER_H
#include <sys/vmmeter.h>
#endif
#endif
#ifdef __linux__
#include <sys/auxv.h>
#endif

//! Necessary on some platforms
extern char **environ; // NOLINT(readability-redundant-declaration)

namespace {
void RandAddSeedPerfmon(CSHA512 &hasher) {
#ifdef WIN32
    // Seed with the entire set of perfmon data

    // This can take up to 2 seconds, so only do it every 10 minutes.
    // Initialize last_perfmon to 0 seconds, we don't skip the first call.
    static std::atomic<std::chrono::seconds> last_perfmon{0s};
    auto last_time = last_perfmon.load();
    auto current_time = GetTime<std::chrono::seconds>();
    if (current_time < last_time + std::chrono::minutes{10}) {
        return;
    }
    last_perfmon = current_time;

    std::vector<uint8_t> vData(250000, 0);
    long ret = 0;
    unsigned long nSize = 0;
    // Bail out at more than 10MB of performance data
    const size_t nMaxSize = 10000000;
    while (true) {
        nSize = vData.size();
        ret = RegQueryValueExA(HKEY_PERFORMANCE_DATA, "Global", nullptr,
                               nullptr, vData.data(), &nSize);
        if (ret != ERROR_MORE_DATA || vData.size() >= nMaxSize) {
            break;
        }
        // Grow size of buffer exponentially
        vData.resize(std::min((vData.size() * 3) / 2, nMaxSize));
    }
    RegCloseKey(HKEY_PERFORMANCE_DATA);
    if (ret == ERROR_SUCCESS) {
        hasher.Write(vData.data(), nSize);
        memory_cleanse(vData.data(), nSize);
    } else {
        // Performance data is only a best-effort attempt at improving the
        // situation when the OS randomness (and other sources) aren't
        // adequate. As a result, failure to read it is isn't considered
        // critical, so we don't call RandFailure().
        // TODO: Add logging when the logger is made functional before global
        // constructors have been invoked.
    }
#endif
}

/** Helper to easily feed data into a CSHA512.
 *
 * Note that this does not serialize the passed object (like stream.h's <<
 * operators do). Its raw memory representation is used directly.
 */
template <typename T> CSHA512 &operator<<(CSHA512 &hasher, const T &data) {
    static_assert(
        !std::is_same<typename std::decay<T>::type, char *>::value,
        "Calling operator<<(CSHA512, char*) is probably not what you want");
    static_assert(
        !std::is_same<typename std::decay<T>::type, uint8_t *>::value,
        "Calling operator<<(CSHA512, uint8_t*) is probably not what you "
        "want");
    static_assert(
        !std::is_same<typename std::decay<T>::type, const char *>::value,
        "Calling operator<<(CSHA512, const char*) is probably not what you "
        "want");
    static_assert(
        !std::is_same<typename std::decay<T>::type, const uint8_t *>::value,
        "Calling operator<<(CSHA512, const uint8_t*) is "
        "probably not what you want");
    hasher.Write((const uint8_t *)&data, sizeof(data));
    return hasher;
}

#ifndef WIN32
void AddSockaddr(CSHA512 &hasher, const struct sockaddr *addr) {
    if (addr == nullptr) {
        return;
    }
    switch (addr->sa_family) {
        case AF_INET:
            hasher.Write((const uint8_t *)addr, sizeof(sockaddr_in));
            break;
        case AF_INET6:
            hasher.Write((const uint8_t *)addr, sizeof(sockaddr_in6));
            break;
        default:
            hasher.Write((const uint8_t *)&addr->sa_family,
                         sizeof(addr->sa_family));
    }
}

void AddFile(CSHA512 &hasher, const char *path) {
    struct stat sb = {};
    int f = open(path, O_RDONLY);
    size_t total = 0;
    if (f != -1) {
        uint8_t fbuf[4096];
        int n;
        hasher.Write((const uint8_t *)&f, sizeof(f));
        if (fstat(f, &sb) == 0) {
            hasher << sb;
        }
        do {
            n = read(f, fbuf, sizeof(fbuf));
            if (n > 0) {
                hasher.Write(fbuf, n);
            }
            total += n;
            /* not bothering with EINTR handling. */
        } while (n == sizeof(fbuf) &&
                 total < 1048576); // Read only the first 1 Mbyte
        close(f);
    }
}

void AddPath(CSHA512 &hasher, const char *path) {
    struct stat sb = {};
    if (stat(path, &sb) == 0) {
        hasher.Write((const uint8_t *)path, strlen(path) + 1);
        hasher << sb;
    }
}
#endif

#if HAVE_SYSCTL
template <int... S> void AddSysctl(CSHA512 &hasher) {
    int CTL[sizeof...(S)] = {S...};
    uint8_t buffer[65536];
    size_t siz = 65536;
    int ret = sysctl(CTL, sizeof...(S), buffer, &siz, nullptr, 0);
    if (ret == 0 || (ret == -1 && errno == ENOMEM)) {
        hasher << sizeof(CTL);
        hasher.Write((const uint8_t *)CTL, sizeof(CTL));
        if (siz > sizeof(buffer)) {
            siz = sizeof(buffer);
        }
        hasher << siz;
        hasher.Write(buffer, siz);
    }
}
#endif

#ifdef HAVE_GETCPUID
void inline AddCPUID(CSHA512 &hasher, uint32_t leaf, uint32_t subleaf,
                     uint32_t &ax, uint32_t &bx, uint32_t &cx, uint32_t &dx) {
    GetCPUID(leaf, subleaf, ax, bx, cx, dx);
    hasher << leaf << subleaf << ax << bx << cx << dx;
}

void AddAllCPUID(CSHA512 &hasher) {
    uint32_t ax, bx, cx, dx;
    // Iterate over all standard leaves
    // Returns max leaf in ax
    AddCPUID(hasher, 0, 0, ax, bx, cx, dx);
    uint32_t max = ax;
    for (uint32_t leaf = 1; leaf <= max && leaf <= 0xFF; ++leaf) {
        uint32_t maxsub = 0;
        for (uint32_t subleaf = 0; subleaf <= 0xFF; ++subleaf) {
            AddCPUID(hasher, leaf, subleaf, ax, bx, cx, dx);
            // Iterate subleafs for leaf values 4, 7, 11, 13
            if (leaf == 4) {
                if ((ax & 0x1f) == 0) {
                    break;
                }
            } else if (leaf == 7) {
                if (subleaf == 0) {
                    maxsub = ax;
                }
                if (subleaf == maxsub) {
                    break;
                }
            } else if (leaf == 11) {
                if ((cx & 0xff00) == 0) {
                    break;
                }
            } else if (leaf == 13) {
                if (ax == 0 && bx == 0 && cx == 0 && dx == 0) {
                    break;
                }
            } else {
                // For any other leaf, stop after subleaf 0.
                break;
            }
        }
    }
    // Iterate over all extended leaves
    // Returns max extended leaf in ax
    AddCPUID(hasher, 0x80000000, 0, ax, bx, cx, dx);
    uint32_t ext_max = ax;
    for (uint32_t leaf = 0x80000001; leaf <= ext_max && leaf <= 0x800000FF;
         ++leaf) {
        AddCPUID(hasher, leaf, 0, ax, bx, cx, dx);
    }
}
#endif
} // namespace

void RandAddDynamicEnv(CSHA512 &hasher) {
    RandAddSeedPerfmon(hasher);

    // Various clocks
#ifdef WIN32
    FILETIME ftime;
    GetSystemTimeAsFileTime(&ftime);
    hasher << ftime;
#else
    struct timespec ts = {};
#ifdef CLOCK_MONOTONIC
    clock_gettime(CLOCK_MONOTONIC, &ts);
    hasher << ts;
#endif
#ifdef CLOCK_REALTIME
    clock_gettime(CLOCK_REALTIME, &ts);
    hasher << ts;
#endif
#ifdef CLOCK_BOOTTIME
    clock_gettime(CLOCK_BOOTTIME, &ts);
    hasher << ts.tv_sec << ts.tv_nsec;
#endif
    // gettimeofday is available on all UNIX systems, but only has microsecond
    // precision.
    struct timeval tv = {};
    gettimeofday(&tv, nullptr);
    hasher << tv;
#endif
    // Probably redundant, but also use all the clocks C++11 provides:
    hasher << std::chrono::system_clock::now().time_since_epoch().count();
    hasher << std::chrono::steady_clock::now().time_since_epoch().count();
    hasher
        << std::chrono::high_resolution_clock::now().time_since_epoch().count();

#ifndef WIN32
    // Current resource usage.
    struct rusage usage = {};
    if (getrusage(RUSAGE_SELF, &usage) == 0) {
        hasher << usage;
    }
#endif

#ifdef __linux__
    AddFile(hasher, "/proc/diskstats");
    AddFile(hasher, "/proc/vmstat");
    AddFile(hasher, "/proc/schedstat");
    AddFile(hasher, "/proc/zoneinfo");
    AddFile(hasher, "/proc/meminfo");
    AddFile(hasher, "/proc/softirqs");
    AddFile(hasher, "/proc/stat");
    AddFile(hasher, "/proc/self/schedstat");
    AddFile(hasher, "/proc/self/status");
#endif

#if HAVE_SYSCTL
#ifdef CTL_KERN
#if defined(KERN_PROC) && defined(KERN_PROC_ALL)
    AddSysctl<CTL_KERN, KERN_PROC, KERN_PROC_ALL>(hasher);
#endif
#endif
#ifdef CTL_HW
#ifdef HW_DISKSTATS
    AddSysctl<CTL_HW, HW_DISKSTATS>(hasher);
#endif
#endif
#ifdef CTL_VM
#ifdef VM_LOADAVG
    AddSysctl<CTL_VM, VM_LOADAVG>(hasher);
#endif
#ifdef VM_TOTAL
    AddSysctl<CTL_VM, VM_TOTAL>(hasher);
#endif
#ifdef VM_METER
    AddSysctl<CTL_VM, VM_METER>(hasher);
#endif
#endif
#endif

    // Stack and heap location
    void *addr = malloc(4097);
    hasher << &addr << addr;
    free(addr);
}

void RandAddStaticEnv(CSHA512 &hasher) {
    // Some compile-time static properties
    hasher << (CHAR_MIN < 0) << sizeof(void *) << sizeof(long) << sizeof(int);
#if defined(__GNUC__) && defined(__GNUC_MINOR__) && defined(__GNUC_PATCHLEVEL__)
    hasher << __GNUC__ << __GNUC_MINOR__ << __GNUC_PATCHLEVEL__;
#endif
#ifdef _MSC_VER
    hasher << _MSC_VER;
#endif
    hasher << __cplusplus;
#ifdef _XOPEN_VERSION
    hasher << _XOPEN_VERSION;
#endif
#ifdef __VERSION__
    const char *COMPILER_VERSION = __VERSION__;
    hasher.Write((const uint8_t *)COMPILER_VERSION,
                 strlen(COMPILER_VERSION) + 1);
#endif

    // Bitcoin client version
    hasher << CLIENT_VERSION;

#ifdef __linux__
    // Information available through getauxval()
#ifdef AT_HWCAP
    hasher << getauxval(AT_HWCAP);
#endif
#ifdef AT_HWCAP2
    hasher << getauxval(AT_HWCAP2);
#endif
#ifdef AT_RANDOM
    const uint8_t *random_aux = (const uint8_t *)getauxval(AT_RANDOM);
    if (random_aux) {
        hasher.Write(random_aux, 16);
    }
#endif
#ifdef AT_PLATFORM
    const char *platform_str = (const char *)getauxval(AT_PLATFORM);
    if (platform_str) {
        hasher.Write((const uint8_t *)platform_str, strlen(platform_str) + 1);
    }
#endif
#ifdef AT_EXECFN
    const char *exec_str = (const char *)getauxval(AT_EXECFN);
    if (exec_str) {
        hasher.Write((const uint8_t *)exec_str, strlen(exec_str) + 1);
    }
#endif
#endif // __linux__

#ifdef HAVE_GETCPUID
    AddAllCPUID(hasher);
#endif

    // Memory locations
    hasher << &hasher << &RandAddStaticEnv << &malloc << &errno << &environ;

    // Hostname
    char hname[256];
    if (gethostname(hname, 256) == 0) {
        hasher.Write((const uint8_t *)hname, strnlen(hname, 256));
    }

#if HAVE_DECL_GETIFADDRS
    // Network interfaces
    struct ifaddrs *ifad = NULL;
    getifaddrs(&ifad);
    struct ifaddrs *ifit = ifad;
    while (ifit != NULL) {
        hasher.Write((const uint8_t *)&ifit, sizeof(ifit));
        hasher.Write((const uint8_t *)ifit->ifa_name,
                     strlen(ifit->ifa_name) + 1);
        hasher.Write((const uint8_t *)&ifit->ifa_flags,
                     sizeof(ifit->ifa_flags));
        AddSockaddr(hasher, ifit->ifa_addr);
        AddSockaddr(hasher, ifit->ifa_netmask);
        AddSockaddr(hasher, ifit->ifa_dstaddr);
        ifit = ifit->ifa_next;
    }
    freeifaddrs(ifad);
#endif

#ifndef WIN32
    // UNIX kernel information
    struct utsname name;
    if (uname(&name) != -1) {
        hasher.Write((const uint8_t *)&name.sysname, strlen(name.sysname) + 1);
        hasher.Write((const uint8_t *)&name.nodename,
                     strlen(name.nodename) + 1);
        hasher.Write((const uint8_t *)&name.release, strlen(name.release) + 1);
        hasher.Write((const uint8_t *)&name.version, strlen(name.version) + 1);
        hasher.Write((const uint8_t *)&name.machine, strlen(name.machine) + 1);
    }

    /* Path and filesystem provided data */
    AddPath(hasher, "/");
    AddPath(hasher, ".");
    AddPath(hasher, "/tmp");
    AddPath(hasher, "/home");
    AddPath(hasher, "/proc");
#ifdef __linux__
    AddFile(hasher, "/proc/cmdline");
    AddFile(hasher, "/proc/cpuinfo");
    AddFile(hasher, "/proc/version");
#endif
    AddFile(hasher, "/etc/passwd");
    AddFile(hasher, "/etc/group");
    AddFile(hasher, "/etc/hosts");
    AddFile(hasher, "/etc/resolv.conf");
    AddFile(hasher, "/etc/timezone");
    AddFile(hasher, "/etc/localtime");
#endif

    // For MacOS/BSDs, gather data through sysctl instead of /proc. Not all of
    // these will exist on every system.
#if HAVE_SYSCTL
#ifdef CTL_HW
#ifdef HW_MACHINE
    AddSysctl<CTL_HW, HW_MACHINE>(hasher);
#endif
#ifdef HW_MODEL
    AddSysctl<CTL_HW, HW_MODEL>(hasher);
#endif
#ifdef HW_NCPU
    AddSysctl<CTL_HW, HW_NCPU>(hasher);
#endif
#ifdef HW_PHYSMEM
    AddSysctl<CTL_HW, HW_PHYSMEM>(hasher);
#endif
#ifdef HW_USERMEM
    AddSysctl<CTL_HW, HW_USERMEM>(hasher);
#endif
#ifdef HW_MACHINE_ARCH
    AddSysctl<CTL_HW, HW_MACHINE_ARCH>(hasher);
#endif
#ifdef HW_REALMEM
    AddSysctl<CTL_HW, HW_REALMEM>(hasher);
#endif
#ifdef HW_CPU_FREQ
    AddSysctl<CTL_HW, HW_CPU_FREQ>(hasher);
#endif
#ifdef HW_BUS_FREQ
    AddSysctl<CTL_HW, HW_BUS_FREQ>(hasher);
#endif
#ifdef HW_CACHELINE
    AddSysctl<CTL_HW, HW_CACHELINE>(hasher);
#endif
#endif
#ifdef CTL_KERN
#ifdef KERN_BOOTFILE
    AddSysctl<CTL_KERN, KERN_BOOTFILE>(hasher);
#endif
#ifdef KERN_BOOTTIME
    AddSysctl<CTL_KERN, KERN_BOOTTIME>(hasher);
#endif
#ifdef KERN_CLOCKRATE
    AddSysctl<CTL_KERN, KERN_CLOCKRATE>(hasher);
#endif
#ifdef KERN_HOSTID
    AddSysctl<CTL_KERN, KERN_HOSTID>(hasher);
#endif
#ifdef KERN_HOSTUUID
    AddSysctl<CTL_KERN, KERN_HOSTUUID>(hasher);
#endif
#ifdef KERN_HOSTNAME
    AddSysctl<CTL_KERN, KERN_HOSTNAME>(hasher);
#endif
#ifdef KERN_OSRELDATE
    AddSysctl<CTL_KERN, KERN_OSRELDATE>(hasher);
#endif
#ifdef KERN_OSRELEASE
    AddSysctl<CTL_KERN, KERN_OSRELEASE>(hasher);
#endif
#ifdef KERN_OSREV
    AddSysctl<CTL_KERN, KERN_OSREV>(hasher);
#endif
#ifdef KERN_OSTYPE
    AddSysctl<CTL_KERN, KERN_OSTYPE>(hasher);
#endif
#ifdef KERN_POSIX1
    AddSysctl<CTL_KERN, KERN_OSREV>(hasher);
#endif
#ifdef KERN_VERSION
    AddSysctl<CTL_KERN, KERN_VERSION>(hasher);
#endif
#endif
#endif

    // Env variables
    if (environ) {
        for (size_t i = 0; environ[i]; ++i) {
            hasher.Write((const uint8_t *)environ[i], strlen(environ[i]));
        }
    }

    // Process, thread, user, session, group, ... ids.
#ifdef WIN32
    hasher << GetCurrentProcessId() << GetCurrentThreadId();
#else
    hasher << getpid() << getppid() << getsid(0) << getpgid(0) << getuid()
           << geteuid() << getgid() << getegid();
#endif
    hasher << std::this_thread::get_id();
}
